title: A novel C-type lysozyme from Mytilus galloprovincialis: insight into innate immunity and molecular evolution of invertebrate C-type lysozymes.
abstract: A c-type lysozyme (named as MgCLYZ) gene was cloned from the mussel Mytilus galloprovincialis. Blast analysis indicated that MgCLYZ was a salivary c-type lysozyme which was mainly found in insects. The nucleotide sequence of MgCLYZ was predicted to encode a polypeptide of 154 amino acid residues with the signal peptide comprising the first 24 residues. The deduced mature peptide of MgCLYZ was of a calculated molecular weight of 14.4 kD and a theoretical isoelectric point (pI) of 8.08. Evolution analysis suggested that bivalve branch of the invertebrate c-type lysozymes phylogeny tree underwent positive selection during evolution. By quantitative real-time RT-PCR (qRT-PCR) analysis, MgCLYZ transcript was widely detected in all examined tissues and responded sensitively to bacterial challenge in hemocytes and hepatopancreas. The optimal temperature and pH of recombinant MgCLYZ (rMgCLYZ) were 20°C and 4, respectively. The rMgCLYZ displayed lytic activities against Gram-positive bacteria including Micrococcus luteus and Staphyloccocus aureus, and Gram-negative bacteria including Vibrio anguillarum, Enterobacter cloacae, Pseudomonas putida, Proteus mirabilis and Bacillus aquimaris. These results suggest that MgCLYZ perhaps play an important role in innate immunity of M. galloprovincialis, and invertebrate c-type lysozymes might be under positive selection in a species-specific manner during evolution for undergoing adaptation to different environment and diverse pathogens.
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, PR China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.forename: Chunyan
authors.initials: C
authors.lastname: Wang
authors.forename: Changkao
authors.initials: C
authors.lastname: Mu
authors.forename: Huifeng
authors.initials: H
authors.lastname: Wu
authors.forename: Linbao
authors.initials: L
authors.lastname: Zhang
authors.forename: Jianmin
authors.initials: J
authors.lastname: Zhao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D006863:Hydrogen-Ion Concentration; D007113:Immunity, Innate / Q000235:genetics*; D007448:Invertebrates / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D049878:Mytilus / Q000201:enzymology / Q000235:genetics*; D010802:Phylogeny; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013696:Temperature
chemical_list: D018076:DNA, Complementary; D011994:Recombinant Proteins; D009113:Muramidase